Tire/wheel assembly and run-flat support member

ABSTRACT

A tire/wheel assembly comprising a wheel having a rim, a pneumatic tire fitted to the rim and a run-flat support member. The pneumatic tire includes a cavity, and the run-flat support member is disposed in the cavity of the pneumatic tire. The run-flat support member includes an annular shell and elastic rings. The annular shell has a support surface located radially outward and two leg portions formed radially inward. The elastic rings support the leg portions on the rim. The leg portions of the annular shell are detachably attached to the elastic rings.

TECHNICAL FIELD

The present invention relates to tire/wheel assemblies and run-flatsupport members, and more particularly, to a tire/wheel assembly and arun-flat support member used therefor, in which the run-flat supportmember can be repaired, and manufacturing efficiency thereof can beimproved.

TECHNICAL BACKGROUND

In response to demands in the market, there have been proposed manytechnologies which allow a vehicle to urgently travel when a pneumatictire thereof is punctured during traveling. These many proposals includesuch a technology disclosed in Japanese Patent Laid-Open Publication No.10-297226 and Published Japanese Translation of a PCT Application No.2001-519279 that a support member is fitted onto a rim in the cavity ofa pneumatic tire which is assembled to the rim, and supports the tirewhen punctured to thereby enable run-flat traveling.

The above run-flat support member comprises an annular shell having asupport surface located radially outward and two leg portions formedradially inward, and elastic rings attached thereto, and is supported onthe rim via the elastic rings. The run-flat support member allowsexisting wheels and rims to be used without any specific modification,and can therefore be advantageously adopted without causing confusionsin the market.

In general, the annular shell of the above-mentioned run-flat member isattached to the elastic rings thereof by bonding to the elastic ringsthe leg portions of the annular shell which are embedded therein whenthe elastic rings are formed by heating, and the annular shell and theelastic rings are unitarily structured so that they are not detachable.Therefore, in the case where either the annular shell or the elasticring is damaged into an unusable state by run-flat traveling at 0pressure after the tire is punctured, a problem arises such that a newrun-flat support member must be purchased even if the other is stillusable.

Also, wheels to mount a tire having the same size have different rimshapes, and the same sized tires have different shapes of the innerfaces of the tire beads with which the elastic rings come into contact,whereby respective run-flat support members having an annular shell andelastic rings corresponding thereto need to be manufactured. Varioustypes of run-flat support members, therefore, have to be manufactured,and there is a problem of very low manufacturing efficiency.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide a tire/wheel assemblyand a run-flat support member, in which the run-flat support member canbe repaired by replacement of a damaged annular shell or elastic ring,and the manufacturing efficiency of the run-flat support member can beimproved.

In order to achieve the above object, a tire/wheel assembly according tothe present invention comprises:

a wheel having a rim;

a pneumatic tire fitted to the rim of the wheel, the pneumatic tirehaving a cavity; and

a run-flat support member disposed in the cavity of the pneumatic tire,the run-flat support member having an annular shell and elastic rings,the annular shell comprising a support surface located radially outwardand two leg portions formed radially inward, the elastic ringssupporting the leg portions on the rim,

wherein the leg portions of the annular shell are detachably attached tothe elastic rings.

A run-flat support member according to the present invention comprises:

an annular shell having a support surface located radially outward andtwo leg portions formed radially inward; and

elastic rings supporting the leg portions on a rim,

wherein the leg portions of the annular shell are detachably attached tothe elastic rings.

As mentioned above, the leg portions of the annular shell is detachablyattached to the elastic rings, and therefore, in the case where eitherthe annular shell or the elastic ring is damaged into an unusable state,it can be removed to replace it. Accordingly, the run-flat supportmember can be repaired.

Respective annular shells and elastic rings matching such conditions asrim shapes are manufactured, and when used (sold), a run-flat supportmember can be fabricated by assembling the annular shell and elasticrings. Therefore, it is not necessary to conventionally manufacturevarious types of run-flat support members having a unitary structure ofan annular shell and elastic rings, thus allowing manufacturingefficiency to be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a meridian cross-sectional view showing a main part of atire/wheel assembly according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing an example of anattachment construction of the leg portion of the annular shell to theelastic ring.

FIG. 3 is an enlarged cross-sectional view showing an alternativeexample of an attachment construction of the leg portion of the annularshell to the elastic ring.

FIG. 4 is an enlarged cross-sectional view showing another alternativeexample of an attachment construction of the leg portion of the annularshell to the elastic ring.

FIG. 5 is an enlarged cross-sectional view showing still anotheralternative example of an attachment construction of the leg portion ofthe annular shell to the elastic ring.

FIG. 6 is an enlarged cross-sectional view showing still anotheralternative example of an attachment construction of the leg portion ofthe annular shell to the elastic ring.

FIG. 7 is an enlarged cross-sectional view showing an example of anattachment construction of the leg portion of the annular shell to anelastic ring having a shape fitting to the rim having a different shape.

FIG. 8 is an enlarged cross-sectional view showing an example of therun-flat support member that enables a position of the elastic ring tobe fine adjusted.

BEST MODES FOR CARRYING OUT THE INVENTION

According to the present invention, a run-flat support member is formedas an annular member to be inserted into the cavity of a pneumatic tire.This run-flat member is formed to have an outer diameter smaller thanthe inner diameter of the cavity of a pneumatic tire so as to maintain aconstant distance from the inner surface of the cavity, and is formed tohave an inner diameter which is approximately equal in size to the innerdiameter of the beads of a pneumatic tire. The run-flat support memberis inserted into a pneumatic tire, and assembled to the rim of a wheeltogether with the pneumatic tire to thereby form a tire/wheel assembly.The tire/wheel assembly is attached to a vehicle, and when the pneumatictire is punctured during traveling, the punctured tire is supported bythe radially outer surface of the run-flat support member to therebyallow run-flat traveling.

The above-mentioned run-flat support member includes an annular sell andelastic rings as main parts.

The annular shell is formed to have a continuous support surface forsupporting a punctured tire on the radially outer side thereof, and isshaped to have two leg portions which consist of left and rightsidewalls in a straddled state on the radially inner side thereof. Theradially outer side support surface is formed such that thecross-sectional shape taken along a plane orthogonal to thecircumferential direction thereof has radially outwardly convexed andcurved surface sections. The number of the convexly curved surfacesections which are aligned in an axial direction of the tire may be one,but preferably, two or more. Formation of the support surface in such away as to align two or more convexly curved surface sections providesthe support surface with two or more dispersed contact points withrespect to the inner surface of the tire to thereby reduce localizedwear on the tire inner surface, and therefore, a run-flat travelingdistance can be extended.

The elastic rings are attached to the ends of the two leg portionsformed in the radially inner side of the annular shell, respectively,and come into engagement with left and right rim seats to therebysupport the annular shell. The elastic rings are formed of rubber orelastic resin, and not only mitigate the vibration and impact of theannular shell receiving from a punctured tire, but also prevent slippingwith respect to the rim seats to thereby stably support the annularshell.

The annular shell is formed of a rigid material due to the fact that therun-flat support member has to support a vehicle weight through apunctured tire. The constituent materials thereof include metal, resinand the like. The metal materials may include, for example, steel andaluminum. The resins may be thermoplastic resins or thermosettingresins. The thermoplastic resins may include nylon, polyester and thelike, and the thermosetting resins may include epoxy resins, unsaturatedpolyester resins, etc. The resins may be used alone or mixed withreinforcing fibers as fiber-reinforced resins.

The elastic rings may be formed of any kind of rubber or elastic rein ifthe annular shell can stably be supported, and the rubber materials mayinclude, for example, natural rubber, isoprene rubber, styrene-butadienerubber, butadiene rubber, butyl rubber.

The run-flat support member used for the tire/wheel assembly of thepresent invention is premised on the structure described above.

The embodiments of the present invention will be described in detailbelow with reference to the drawings.

FIG. 1 is a meridian cross-sectional view illustrating a main part of atire/wheel assembly according to an embodiment of the present invention,in which reference numeral 1 denotes a rim in the outer periphery of awheel, reference numeral 2 denotes a pneumatic tire, and referencenumeral 3 denotes a run-flat support member. The rim 1, pneumatic tire2, and run-flat support member 3 are in coaxial alignment with eachother around the axis (not shown) of rotation of the wheel to be in theform of an annulus, which has an arrangement such that the run-flatsupport member 3 is placed in the cavity 2A of the pneumatic tire 2mounted on the rim 1.

The run-flat support member 3 comprises an annular shell 4 formed of arigid material such as metal or rein, and left and right elastic rings 5formed of an elastic material such as rubber or elastic resin.

The annular shell 4 has a support surface 6 formed on the radially outerside thereof, which consists of two convexly curved surface sections 6 awith a radius of curvature aligned in the shell width direction, and thesupport surface 6 is spaced apart from the inner surface 2 a of thepneumatic tire 2 when the pneumatic tire 2 is under a normal condition,and when punctured, the support surface 6 supports the punctured tire.The annular shell 4 also has two side walls formed as leg portions 7 onthe radially inner side thereof, and the elastic rings 5 are detachablyattached to the radially inner sides of the leg portions 7.

The attachment constructions of the leg portions 7 to the elastic rings5 shown in, for example, FIGS. 2 to 7 may be employed.

Referring to FIG. 2, the leg portion 7 formed in an L-shaped crosssection is releasably fixed at an attachment section 7 a thereof bybolts 8 to the radially outer surface 5 a of the elastic ring 5 which isin the shape of a parallelogram in cross section. The attachment section7 a is formed in a ring shape having a width extending in a direction ofthe rotation axis of the wheel, and has insert-through holes m forinserting the bolts 8 therethrough in a predetermined interval along itscircumferential direction. The attachment section 7 a is directly fixedto the radially outer surface 5 a of the elastic ring 5 which isparallel to the wheel rotation axis by the bolts 8 each having a boltaxis b which extends in a radius direction of the wheel perpendicular tothe wheel rotation axis.

Each bolt 8 may be directly screwed into without any fabrication in theradially outer surface 5 a of the elastic ring 5, or may be screwed intoa preformed hole for indicating a fixed position of the bolt, thediameter of which is smaller than that of the bolt. Alternatively, thebolts 8 may be threaded into threaded screw holes which are formed inthe radially outer surface 5 a of the elastic ring 5 in such a mannerthat the bolts can be threadedly engaged.

Referring to FIG. 3, a ring-shaped fixing component 9, formed of metalor synthetic rein, for threading the bolts 8 is disposed on the radiallyouter surface 5 a of the elastic ring 5 which is in the shape of aparallelogram in cross section. The fixing component 9 is integrallyattached to the elastic ring 5 by integral bonding of the fixingcomponent to the elastic ring during formation of the elastic ring.Formed through the fixing component 9 in a predetermined interval alongits circumferential direction are threaded screw holes n into which thebolts 8 can be threaded.

The attachment section 7 a of the leg portion 7 is releasably fixed tothe elastic ring 5 by the bolts 8 which are threaded into the threadedscrew holes n through insert-through holes m formed in the attachmentsection 7 a of the leg portion 7. Provision of the fixing component 9 onthe elastic ring 5 described above allows the annular shell 4 to be morefirmly fixed to the elastic rings 5 than in the case of FIG. 2.

In the alternative of the above-mentioned ring-shaped component, thefixing component 9 may be composed of a plurality of plate pieces whichare integrally bonded to the radially outer surface 5 a at respectivelocations corresponding to the fixing positions.

Referring to FIG. 4, the elastic ring 5 which is in the shape of aparallelogram in cross section has an insert slot s, circularlyextending along a circumferential direction of the ring, in an innersurface 5 b thereof for inserting the attachment section 7 a of the legportion 7 extending in a direction of the wheel rotation axis. The legportion 7 is fixed to the elastic ring 5 by the bolts 8, which arethreaded into the elastic ring 5 from the radially outer surface 5 a ofthe elastic ring 5 and inserted through the insert-through holes m ofthe attachment section 7 a put into the insert slot s.

Referring to FIG. 5, in the construction of FIG. 4, the insert slot s iswider in width, and the fixing component 9 is attached into the insertslot s by integral bonding during formation of the elastic ring. Thefixing component 9 includes a radially outer ring portion 9 a, aradially inner portion 9 b, and a ring-shaped slot 9 c formed betweenthe radially outer ring portion 9 a and the radially inner portion 9 b,and the radially outer ring portion 9 a has threaded screw holes n forthreading the bolts 8 which are formed therethrough in a predeterminedinterval along the ring circumferential direction. The radially innerportion 9 b has insert-through holes x formed at locations correspondingto the above threaded screw holes n in a predetermined interval alongthe ring circumferential direction.

The attachment section 7 a of the leg portion 7 is put into thering-shaped slot 9 c, and the leg portion 7 is fixed to the elastic ring5 by the bolts 8, which are threaded into the elastic ring 5 from theradially outer surface 5 a of the elastic ring 5 to thread the bolts 8into the threaded screw holes n, and are inserted through theinsert-through holes m of the attachment section 7 a and theinsert-through holes x of the radially inner ring portion 9 b.

Referring to FIG. 6, the attachment section 7 a of the leg portion 7 isnot bent in an L shape in cross section, but has a shape which extendsalong the inner surface 5 b of the elastic ring 5, and the attachmentsection 7 a is releasably fixed to the inner surface 5 b of the elasticring 5 by the bolts 8.

Referring to FIG. 7, an example is shown of the case where the legportion 7 of the annular shell 4 is coupled to the elastic ring 5 havinga shape fitting to the rim or the like having a different shape, and asin FIG. 2, the attachment section 7 a of the leg portion 7 is directlyreleasably fixed to the radially outer surface 5 a of the elastic ring 5by the bolts 8. The elastic ring has a shape corresponding to the humpshape of a fitting rim and to the inner shape of the bead of a fittingtire.

The run-flat support member 3 constructed as described above is insertedinto the pneumatic tire 2 when assembled to the rim, and the elasticrings 5 are then fitted onto the rim seats 1s of the rim 1 together withthe beads 2 b of the pneumatic tire 2 simultaneously.

According to the present invention mentioned above, the leg portions 7of the annular shell 4 is detachably attached to the elastic rings 5,and therefore, in the case where either the annular shell 4 or theelastic ring 5 is damaged into an unusable state, it can be removed toreplace it. Thus, the run-flat support member 3 can be repaired.

Respective annular shells 4 and elastic rings 5 matching such conditionsas rim shapes are prepared, and when used (sold), a run-flat supportmember can be fabricated by assembling the annular shell and elasticrings. Therefore, it is not necessary to conventionally manufacturevarious types of run-flat support members having a unitary structure ofan annular shell and elastic rings, thus allowing manufacturingefficiency to be improved.

FIG. 8 shows an example of the run-flat support member 3 that allows aposition of the elastic ring 5 to be fine adjusted. Prepared are aplurality of (two in the drawing) elastic rings 5A and 5B havingthreaded screw holes n for threading the bolts 8 in the radially outersurface 5 a, the threaded screw holes n of the respective elastic ringsbeing displaced in a direction of the wheel rotation axis, and the legportion 7 of the annular shell is fixed to one properly selected fromthe plurality of the elastic rings 5A and 5B by the bolts 8 as in FIG.2. This allows a fine adjustment of a distance between the left andright elastic rings 5 in correspondence with a tire/wheel assembly towhich the elastic rings are to be fitted, using the same annular shell4.

In the present invention, the foregoing bolts 8 may be formed of metalor synthetic resin. The metal materials may include, for example, steeland aluminum. The synthetic resins may be thermoplastic resins orthermosetting resins. The thermoplastic resins may include, for example,nylon and polyester, and the thermosetting resins may include, forexample, epoxy resins and unsaturated polyester resins.

As shown in FIGS. 2 to 5, 7 and 8, in the case where the attachmentsection 7 a of the leg portion 7 extending in the wheel rotation axisdirection is fixed to the elastic ring 5 by the bolts 8 which have abolt axis b (see FIG. 2) extending in a radial direction of the wheel,the bolts 8 are preferably formed of synthetic resin in terms of weightsaving since a great shearing force (a force acting in a directionorthogonal to the bolt axis b) is not applied to the bolts 8 by thefixed attachment section 7 a. The bolts 8 are preferably formed of metalin the case of the example shown in FIG. 6.

The metals and synthetic resins used for the fixing component 9 may bethe same as those of the bolts 8. The metal materials may include steel,aluminum and the like, the thermoplastic resins may include nylon,polyester, etc., and the thermosetting resins may include epoxy resins,unsaturated polyester resins and so on.

The attachment section 7 a of the leg portion 7 extends from the legbody section 7A thereof towards the outer side of the width direction ofthe run-flat support member 3 in the above embodiments (except FIG. 6),but may be arranged so as to extend inwardly from the outer side of thewidth direction.

The attachment sections 7 a of the left and right portions 7 may besymmetrical or asymmetrical in shape with respect to the center line ofthe annular shell. In the case of shaping asymmetrically, for example,the leg portion 7 on the outer side of a vehicle when attached theretois bent axially inwardly (inwardly in a width direction of the run-flatsupport member 3) to form the attachment section 7 a, while the legportion 7 on the inner side of a vehicle when attached thereto isaxially outwardly bent to form the attachment portion 7 a, as shown inFIGS. 2 to 5, 7 and 8. In this case, the annular shell is attached to beoffset towards the outer side of a vehicle to which a greater load isapplied, thus improving durability. The leg portions 7 may also beformed, for example, to have different tilt angles.

The foregoing embodiments exemplify the cases where the support surface6 of the annular shell 4 has two convexly curved surface sections 6 aand 6 a. However, the number of the convexly curved surface sections isnot limited to two, but may be one, or three or more.

The attachment of the annular shell 4 to the elastic rings 5 ispreferably performed by the bolts 8, as described above, since theannular shell 4 can strongly be fixed to the elastic rings 5. However,other fixing members may be employed to fix it.

As illustrated above, according to the present invention, the annularshell is detachably attached at the leg portions thereof to the elasticrings, and therefore, the annular shell or the elastic ring can bereplaced when broken to thereby repair the run-flat support member, aswell as the manufacturing efficiency of the run-flat support members canbe improved.

INDUSTRIAL APPLICABILITY

The present invention having the aforementioned excellent effects isvery effectively applicable to a tire/wheel assembly which is to beattached to a vehicle and allows run-flat traveling, and to a run-flatsupport member used therefor.

1. A run-flat support member comprising: an annular shell having asupport surface located radially outward and two leg portions formedradially inward; elastic rings supporting the leg portions on a rim; anda plurality of elastic rings having threaded screw holes for threadingthe bolts, the threaded screw holes of the respective elastic ringsbeing displaced in a direction of a rotation axis of a wheel, each ofthe leg portions of the annular shell being fixed to one selected fromthe plurality of the elastic rings, wherein the leg portions of theannular shell are detachably attached to the elastic rings, and whereinthe leg portions are releasably fixed to the elastic rings by bolts. 2.A run-flat support member according to claim 1, wherein the elasticrings have a fixing component for threading the bolts, the fixingcomponent being formed of metal or synthetic resin.
 3. A run-flatsupport member according to claim 1, wherein each of the leg portionshas an attachment section which extends in a direction of a rotationaxis of a wheel, the attachment section being fixed to the elastic ringby the bolts having a bolt axis extending in a radial direction of thewheel.
 4. A run-flat support member according to claim 3, wherein thebolts are formed of synthetic resin.
 5. A tire/wheel assemblycomprising: a wheel having a rim; a pneumatic tire fitted to the rim ofthe wheel, the pneumatic tire having a cavity; and a run-flat supportmember disposed in the cavity of the pneumatic tire, the run-flatsupport member having an annular shell and elastic rings, the annularshell comprising a support surface located radially outward and two legportions formed radially inward, the elastic rings supporting the legportions on the rim; and a plurality of elastic rings having threadedscrew holes for threading the bolts, the threaded screw holes of therespective elastic rings being displaced in a direction of a rotationaxis of the wheel, each of the leg portions of the annular shell beingfixed to one selected from the plurality of the elastic rings, whereinthe leg portions of the annular shell are detachably attached to theelastic rings, wherein the leg portions are releasably fixed to theelastic rings by bolts.
 6. A tire/wheel assembly according to claim 5,wherein the elastic rings have a fixing component for threading thebolts, the fixing component being formed of metal or synthetic resin. 7.A tire/wheel assembly according to claim 5, wherein each of the legportions has an attachment section which extends in a direction of arotation axis of the wheel, the attachment section being fixed to theelastic ring by the bolts having a bolt axis extending in a radialdirection of the wheel.
 8. A tire/wheel assembly according to claim 7,wherein the bolts are formed of synthetic resin.